John Deere 970 3-pt hitch has gotten wonky

[landev]

The height adjustment of my 3 point has gone south. The hitch does no raising of the attached implement (613 mower) until the raise lever is almost all the way up (8 on the scale printed below the lever.) Once it starts to rise, it goes all the way to the top of the rockarm travel. Trying to lower gradually doesn't work. I get to ~ 8 on the scale and the mower drops to the ground. Has anyone experienced this before and if so,could you please let me know where the fault (seal, I suspect) might be? I'm hoping for the drop rate valve being the culprit, but I'm guessing it's in the rockarm adjustment portion. If the latter is true, can the repair be made with it on the tractor or do I have to remove?

Thanks much in advance!

-l-

 

[Seven Gables]

Sounds like your trying to use it in draft control instead of position control. I'm not familiar with 970 though but assume it has both draft and position control for the 3pt hitch

 

[landev]

Sounds like your trying to use it in draft control instead of position control. I'm not familiar with 970 though but assume it has both draft and position control for the 3pt hitch

I bought this tractor new back when Moses was a kid, so don't recall all the particulars, but seem to recall that the 970 does not have draft control... but the 1070 does.

I should mention that the machine worked fine until just recently... I spoke with a JD mechanic and he said it could be any of numerous O-rings. As the tractor is now 25 years old and I've not done anything to the hydraulics other than change the oil, I'm sure that the issue of wear is not out of the question. I only have ~ 700 hrs. on the machine... have babied it for the most part... perhaps I'm expecting too much to think all components will last forever, eh?

Thanks for taking the time to reply!

-l-